1. Field of the Invention
The present invention relates to the field of piles used in forming various structures, including a device and method for repairing damaged metal piles.
2. Description of Related Art
Piles of concrete, timber, steel or composite materials are an integral structural part of marine structures such as bridges, docks, piers, wharfs and the like. Piles, which are driven or jetted into the ground to some determined depth, support a structure above the water's surface. A disadvantage associated with metal or steel piles is that portions of the piles are susceptible to corrosion and/or degradation due at least in part to being located in a water environment, exposure to corrosive and/or salty air, impact from boats and other water vessels, and exposure to chemicals in the water, among other things. Even though steel piles are typically waterproofed prior to their installation, over a period of time, the waterproofing is usually not durable or protective enough to prevent the steel from corroding. Most of the damage to the piles tends to occur at the water line due to the wave action at that location. This wave action tends to be aggravated by the tides that are prevalent at many pile installations, where at high tide, water covers a greater height of the pile, while at low tide, a greater length of the pile is exposed to the air. Therefore, the piles undergo drying and wetting cycles that tend to contribute to further corrosion, thus weakening the piles at their mid sections.
While various encasement, wrapping and replacement techniques have emerged for the repair of the inevitable damage to steel piles, these techniques have some shortcomings. Encasement and wrapping may be suitable if the damage has not seriously compromised the structural integrity of the piles. However, for more serious damage, these practices are not particularly desirable as the structural strength of the repaired pile remains impaired. To repair more serious damage, a section of the pile may have to be replaced, or the pile may have to be replaced in its entirety. Furthermore, conventional replacement techniques tend to be costly, time and labor intensive, and complex.
U.S. Pat. No. 6,773,206 of DENSO™ North American Corporation describes the use of cylindrical fiber-form jackets, such as fiberglass or nylon, that are placed over the whole length of the pile to be repaired, or over the damage at the pile's tidal zone. The fiber-form jackets may be filled with concrete. The same patent also describes that the ROCKWATER Corporation in Farmingdale N.Y. discloses a similar system for damaged pile sections surrounded by fiberglass and nylon reinforced pile jackets filled with concrete. U.S. Pat. No. 6,773,206 also discloses a jacket having two halves that have been bolted together around a damaged pile. However, the fiberglass and nylon materials used in these jackets tend to be quite costly. Further, the jackets are hard to install, particularly underwater, making for an extremely cumbersome installation process, which makes such installation time consuming and labor intensive. Adding to these problems is that great care must be taken when handling fiberglass jackets, as they are quite delicate. Further, these jackets do not serve to significantly improve the structural strength of the repaired pile. In fact, the jackets tend to deteriorate over time, and may even separate and become detached from the pile, providing no compressive strength to the damaged pile at all. Additionally, these types of jackets, which are usually cylindrical, take up a lot of space. This in undesirable where repairs are being made under mud piles, as the large footprint created by the jacket may not fit within the confines of the area authorized by environmental permits for this type of installation. It is also known in the art, including U.S. Pat. No. 6,773,206, that a plastic jacket may be used with alternative filled jackets which suffer from many of the same issues associated with the fiber-form jackets.
U.S. Pat. No. 6,561,736 describes a coupler having steel sheathing members clamped against an H-pile in a particular configuration. An embodiment designed for H-piles further includes two channel members placed in each channel of the H-pile, and a locking bar member located along the longitudinal edge of the H-pile.
U.S. Pat. No. 5,813,800 describes an H-pile coupler having flat steel plates bolted to the flat sides of the H-pile, and a replacement H-pile section fastened to the flat steel plate reinforcement members. This patent teaches removal of the damaged pile section prior to installation of the coupler and replacement H-pile.
Even in view of the prior art designs, there remains a longstanding need in the art for alternative devices and methods for repairing piles which protect and structurally reinforce a pile.